Toroidal transmission



Jan 3, 1950 R. CHILTON TOROIDAL` TRANSMISSION 3 Sheets-Sheet 1 Filed Oct. 6, '19,44

INVENTR HDI-'AND CHILTUN ATTORNE Jan. 3, 1950 R. CHILTON 2,493,571

TOROIDAL TRANSMISSION Filed oct. s, 1944 s sheets-sheet 2 Ililll INVENTOR. HDL AND EHILTUN.

Jan. 3,'1950 v R. clHlL'roN 2,493,571

TOROIDAL TRANSMI SS ION Filed Oct. 6, 1944 v 3 Sheets-Sheet 3 1E E 49 INVENTOR.

RDLAND CHILTDN ATTDRNY Patented Jan. 3, 1950 UNITI-:D STATES PATENT OFFICE' TOROIDAL TRANSMISSION Roland Chilton, Ridgewood, N. J., assigner to Allan Chilton and William E. Valk, both of Ridgewood, N. J., doing business as joint adventurers Application October 6, 1944, Serial N0. 557.477

(Cl. i4-200)` 26 Claims.

. tact being variable by angulation of the rollers.

In the above type transmission, the toroidal discs are forced against the rollers to obtain tractive effort by a force known as the contact load and the ratio changing angulation of the rollers is effected while they are under this load. To this end the rollers are mounted for angulation on axes tangential to the pitch circle of the toroidal disc faces.

It is known in the art that the ratio changing motion of the rollers cannot be directly and frocibly produced by sliding them under their contact load. The plane of each roller isnormally tangential to its contact paths on the as sociated discs and while this condition is maintained, the roller will be stabilized in a given ratio position. However, should the roller be disbeen required to prevent the control from being operated so as to give an undesirably rapid rate of speed-ratio change. For instance, hydraulic l controls and/or a small control wheel geared down to require a great number of 4turns to traverse the full ratio range have been used. It will be understood that while the overall ratio changing swing of the roller may amount to 30 or 40 yet l the steering tilt (ofI-tangency) necessary to produce this angular movement in a few seconds is usually less than 1. Nevertheless, in the prior art compound pivots and/or spherical bearings permitting much more than 1 steering tilt in the roller support have been provided.

I have found that where the roller journal is supported on a simple pin or pivot tangent to the toroidal pitch circle, the inherent looseness or transaxial play in such a pivot connection when constructed with normal clearance is sufiiclent to allow fr the necessary small angle of steering tilt without extraneous pivot means. Where faster rate of ratio change is desired, one of the holes to which the pivot pin is fitted may f be slightly bell-mouthed.

placed to a slightly oit-tangential position, its l contact path on the toroidal discs will depart from the normal circle and will become spiral, the pitch of which depends on the amount of offtangency displacement of the roller.

ample, should a roller running in tangential position on a toroidal d isc contact circle, of say 20" circumference, be displaced to 1 offtangency,

the roller contact will precess radially of the disc approximately .35" per turn. At 10 revs./sec. disc speed, the roller contact will travel radially of the discs 3.5" per sec. Such radial shift of the roller will, in many cases, correspond to the entire ratio range of the transmission which would, accordingly, be covered in l sec. at the low rotational speed of 10 revs./sec. This is a faster rate of change than is generally necessary or desirable and, accordingly, it will be seen that the maximum off-tangency or steering angle required is small and will, in general, be less than 1. However it is within the scope of this invention to provide larger steering angles if a faster rate of speed ratio change is desired.

In the prior art, Where rollers have been.

'I'he forces exerted on each roller by its opposed toroidal discs are each tangential to the roller contact circles thereon and therefore the reaction force maintaining the roller in position relative to said discs isaxial of the aforementioned roller mounting pivot pin. The preferred construction comprises a roller journal member, slotted to accommodate a supporting arm and pivoted thereto on a pin tangent to the toric pitch circle. Thus, the roller driving load reaction devolves on the abutting faces of the supporting arm andof the slot in the roller journal member and, according to a further provision of this invention, these slot faces are relieved to define a narrow contact -zone extending slightly on each side of the midplane of the roller. With this construction, .the roller driving force reaction exerted on its supporting arm tends to stabilize the roller against this narrow abutment in a position tangential to the torio pitch circle, and the roller must be rocked slightly against this roller stabilizing force in order to. tilt the roller to initiate a ratio change. It thus results that the force required to produce a given rate of change is proportional to the roller driving force generated by the resulting acceleration or deceleration of the driven means. In other words, a relatively high rate of ratio change will be opposed by a relatively high roller stabilizing force so that greater effort on the control is needed to produce a greater rate of acceleration. This tends to stable operation tween a central disc and a pair cf opposed end discsA which latter discs are secured to rotate' Figure 3 is a perspective view of one of the roller r Journals;

togetherv with Aa main shaft. The transmission i is contact-loaded by suitable axial pressure means between the shaft and the end discs by which the rollers are compressed between and against the three discs, the shaftcomprising a tension member forV this purpose. In fact the transmis-v sion may be'contact loaded by an axial pressure proportional tothe torque, e. g., as disclosed in my 'prior Patent No. 2,079,683.

It will be seen that in this double-sided. transmission, the rollers of the two sets must pivot equally but in opposite directions in order that the driving ratio of each set of rollers shall be equal (though variable). One set of rollers in provided with an outer support frame and an inner control Aframe while the disposition is vice versa for Vthe other set of rollers. These four framesare held against relative rotation while the control frames for the two sets of rollers are movable axially as a rigid unit to produce the offtangency steering displacement and to follow up the resulting ratio changing precession of the rollers; A further feature of the invention consists ofa novel control connection between the -control frames and the rollers whereby these steering, precession and follow-up functions are effected. Y

i The transmission is equipped with planet gears drivably connected between the center disc and the main shaft and mounted on the output member of the transmission whereby zero drive ratio and reverse drive ratios are obtainable, e. g., as fully `descri-bed in vmy said prior Patent No. 2,079,683.

A further feature of applicants invention lies in the fact that the control frames are restricted to axial control movements for tilting the rollers in order to effect a speed ratio change. In the prior art, tilting of the rollers is effected by a rotary movement of the control frame or frames and therefore, the spacing between adjacent rollers had to be suiiicient to accommodate this rotary movement, whereas -with only axial control movements, as in the present invention, the rollers may be disposed quite close together. For example, I am able to Ause four rollers between a pair of toroidal discs, where with the rotary control movement of the prior art only three rollers were possible.

Objects and advantages of the invention will Figure 4 is a sectional view taken along line I-I of Figure 3; Figure 5 is -a sectional view taken along line 5 5 of Figure 4; and

Figure 6 is a view of a slight modification of the construction illustrated in Figure 5.

Referring first to Figures l and 1A, I0 designates a main drive shaft having a shoulder l2 and a screw thread I4. Abutting the sho'ulde;- I2 is an end disc I6 having a toroidal surface generated by rotation of a circular arc of radius R about the axis 0f shaft I0. A complementary end toric disc I 8 is provided, and both discsare keyed to the shaft I0 for rotation therewith. Between these discs is ay central double toric disc 20 rotatable on a bearing sleeve 22. lThe generating element of each toric surface is a circular arc of radius R and the generating arcs of facing toric surfaces have common centers. The locus 4of such common centers between each pair of facing toric surfaces is a circle which herein is termed a toric pitch circle. Between the central disc 20 and each en d disc I6 and I8 and drivably engaging their opposed toric facesiare sets of similar rollers 24 and 26 respectively. loaded into friction driving contact with the discs by a nut 28 and washer 30. Secured to the central disc 20 is a drum 32 at the left hand end of which a ring gear 3l is integrally formed and to which a cover plate 36 is secured. A sun gear 38 is formed integral with the left hand end disc' I8.- Planet pinions 40 are meshed withv both the gears 3l and 38, and

are mounted on trunnions .42. carried by a disc M y lslots I8 which accommodate radially extending supporting arms 60 and 62 respectively. The arms 60 for the right hand set of rollers 24 extend inwardly from a rim- 63 united by radial spokes 6I to a sleeve 56, and-the arms 52 for the left hand set of rollers 26 extend outwardly from a sleeve 68 surrounding thesleeve 56 and held from rotation relative thereto by a key 58. The spokes -64 are disposed between the rollers 24 as bestrseen in Figure 1A and their rim 53 is connected to a fixed housing 6| within which the transmission is disposed, thereby preventing rotation of the rollers about the axis of the transmission. Instead of connecting the rim 53 directly to the housing 6 I, torque responsive means may be interposed therebetween for providing an axial contact load between the discs i6, I8 and 20 and their rollers proportional to the torque transmitted, e. g., as disclosed in my said prior patent.

Hinge pins 60 pivotally mount the slotted roller Journal members 48 on the arms 50 and 52, said hinge pins being disposed tangent to the toric pitch circles about which the opposed toric faces of ldiscs I6 and 20 and discs I8 and 20 respectively are formed. Each of the rollers 24 and 26 has a diameter which is equal to twice the radius R of the circular generating arc of the toric surfaces. 'Ihe roller journal members or carriers 48 each have a pair of projections 62 providing spaced opposed faces 63 disposed parallel to and on opposite sides of the axis of the associated roller carrier. and at an angle to the axis of the associated pivot pin 60, which angle, for example, is illustrated as 45,.as best seen in Figure 2. Slidably iltted between the Iparallel opposed faces 82 of each pair of projections 42 is a. control block 84, slotted to receive control arms 8l, extending radially inwardly from a control frame rim 58 in the case of the left hand set of rollers 25 and to receive control arms 10 extending radially outwardly from a control sleeve 12 in the case of the right hand set of rollers 24. The control frame rim 88 is rigidly united by radial spokes 14 to a hub 18 rigid with the control sleeve 12, the spokes 14 extending between the rollers 2-5 in a manner similar to the relative disposition of the rollers 24 and spokes 54. The control blocks i4 are pivoted to the control frame arms 88 or 18 by pivot pins 81 disposed parallel to the associated roller mounting pivot pin 58. 'I'he control sleeve 12 is fitted to slide axially within the carrier frame sleeve 58 and is guided against rotation during this motion |by a. pin 18 slidably engaging a control arm 80 extending from said control sleeve, said -pin 18 being rigid with one of the support spokes 54 of the fixed rim 52.

The relative angular disposition of the control projections 82, their control faces 83, control block 84 and the control arm 68 (or 10) is best seen in Figure 2 inwhich the path of movement of the control arm 86 is indicated by the double ended arrow Y which is parallel to the yaxis of shaft I8.

It will be seen that thte members 82, 84, 88 and 81 comprising the control connection of the left hand vset of rollers 2-8 are disposed outboard of the rollers, whereas the members 62, 84, 81 and 18 comprising the control connection of the right hand set oi' rollers 24 are disposed inboard of the associated rollers so that unitary axial movement of the rigidly connected members 80, 12, 15, 14 and 58 comprising a composite, control frame, will move the rollers 24 and 28 through equal ratio changing angles but in opposite directions.

The roller support arms 50 and 52 may be regarded as a rigid unitary structure connected by key 58 through the sleeves 58 and 56 (around which the center disc bearing 22 rotates) and through which the control sleeve 12 is free to be moved axially. The spokes 54 of the support frame pass between adjacent rollers 24 and the spokes 14 of the control frame 68 pass between adjacent rollers 26. The control arm 80, rigid with the control frame, is moved axially through suitable control means by a pivotally supported control lever 8l (illustrated only in Figure 1A) having a pivot pin 83 with a tongue portion en gaged within a slot 82 in the outer end of the control arm 88.

Considering now only the two upper rollers 24 and 25 as illustrated in Figure 1, suppose that the control arm 80 is urged to the right with driving contact loads imposed upon the toroidal discs and rollers. Then it will be seen that the control block 84 of the upper roller 24 will press one of its associated projections 62 so as to urge the upper right hand roller 24 to rotate about its pivot pins 60 in a counter-clockwise direction whereas the control arm 86 and control block 84 will urge the upper roller 28 in a clockwise direction. Due to the heavy contact loads between the rollers and the associated toric surfaces engaged thereby, the rollers cannot respond to this urging. However, because of the angular disposition of the faces S3 of the projections 62, the rollers are also urged to tilt about axes through their points of contact with their opposed toric surfaces as the control arm 88 is urged te the right or left. As a result, when the control arm 88 is urged to the right, the upper roller 24 will be urged to tilt counter-clockwise about an x-:c axis passing through the points of contact of the roller with its opposed toric surfaces, as viewed leftward along this axis, and the upper roller 28 will be urged to tilt counter-clockwise about the axis passing through its points of contact with 7-5itsclf from a circular path to a spiral path on its opposed toric surfaces as viewed from the left in Figure l. Suicient looseness is provided by the tit of the pivot pin in the arms 58 or 52 and by the fit of arms 50 or 52 in the slot in the journal member 44 to permit a slight tilt of the rollers 24 and 25 about individual axes passing through their points of contact on their opposed toric surfaces. As previously mentioned, the bore in the arms 58 or 52 for the pivot pins 58 may be slightly bell-mouthed'to increase the looseness of the ilt oi' the pins 80. For clarity this construction has been exaggerated at 80 in Figure 5. Corresponding looseness at the control pivot pins 81 is not essential since the inclination of the control faces 62 relative to the pivot pins 51 provides a universal joint action by rotation of the control blocks 84. This is true because this inclination is designed greater than the self locking friction angle of the contacting surfaces.

Accordingly, when the control arm 88 is urged to the right. each of the rollers 24 is tilted to an off-tangency position relatively to its associated toric pitch circle. That is, each roller 24 is tilted counter-clockwise about an individual axis passlng through its points of contact with the toric surfaces as viewed from the left in Figure 1, whereby the rollers 24 will be steered from their normal circular paths of contact with their associated toric surfaces to precess along spiral paths thereon. The opposed discs I6 and 20 are rotating in opposite directionsv and with the disc I8 rotating in the direction indicated by the arrow Z on Figure l, this spiral path of speed-ratio changing precession of the rollers 24, resulting from movement of control arm 88 to the right, will be inwardly along the disc i6 and outwardly along the disc 28. Similarly, as a result of the control arm 50 being urged to the right, the rollers 28 tilt about axes through their points of contact with their opposed toric surfaces in a direction such that the resulting precession of the rollers 28 along spiral paths will be inwardly along disc i8 and outwardly along the disc 20. Thus upon movement of the control arm 80 the two sets of rollers 24 and 28 respectively rotate in opposite directions about their pivot pins 8l. Obviously shift movement of control arm 88 to the left will result in speed-ratio changing precession of rollers 24 and 28 opposite to that resulting from shift movement of the control arm to the right.

This speed-ratio changing precession of the rollers 24 and 28 will persist as long as it is followed up by movement of the control arm 88 and the unitary control frame connected thereto. However, as soon as the control arm 38 is held stationary, the next increment oi precession of the rollers24 and 28 will remove the tilting pressure exerted by the control blocks 54 on their associated rollers through the projections 82, and

any further precession is prevented by a resulting reversal of the tilting pressure, thereby restoring the rollers to a tangent disposition relative to their associated toric pitch circle, and as a result each roller stabilizes with a circular contact path on each of its associated toric surfaces. That is, with the control arm B0 locked, any incidental Vtendency of any roller to displace its associated torio surfaces is instantly corrected by the restoring force generated by the angular control faces 63. f

In order that the rollers shall precess in a direction to remove the tilting pressure exerted by the control blocks on the roller journal projections 62, the hand or direction of the slope of the faces 63 of the control projections 62 must be correlated with the direction of rotation of the associated toric discs. The disposition oi' the control faces 63 illustrated in Figure vl is appropriate for a, direction of rotation of the end discs I6 and `I8 indicated by the arrow gc. Incidentally the upper roller 24 is shown in axial section in Figure 1 and therefore, onlyone of the control projections 62 is illustrated, the opposed companion projection 62 being above the plane ofthe section.

The rate at which the precession ofthe rollers takes place depends upon the angle through which the rollers are tilted by the displacement of the control arm 80, but it should be noted that control force sc long, and only so long as the control force persists.

The control projections 62 are shown as integral with the journal members 48 on which the rollers are retained with minimum end play by a detachable plate 84 secured to the .Journal members 48 and provided with holes 66 to'clear the projections 62. Obviously, however, the projections 62 could just as well be formed integral with the plates 64. The rollers of the'lefI: and right hand sets 26 and 24 are rotating in opposite directions and have their control projections 62 projecting on opposite sides. From this disposition it results that the hand of the slope of control faces 63 of the projections 62 is the-same for both sets of rollers. i. e., .the rollerjournal members 48 and control blocks 64 may be identical parts for any one pre-selected direction of rotation for the toroidal discs.

Referring now -to Figures 3-5 .illustrating a roller journal or carrier 48. it will be seen that the sides of its slot 49 which accommodates a support arm .56 or 52 have been angularly relieved at 86 to provide a relatively narrow land or abutment face 88-central with the supporting pin 66. The driving load reaction force on each roller is exerted by its fixed supporting arm 60 or 52 to maintain the roller in a. ilxed position about the axis of the shaft I and this roller driving force reaction is exerted by the arm 56 or 52 against one of the narrow land or abutment faces 88 of the roller journal. This reaction force between a flat abutment face 88 -of each roller and its supporting arm 50 or 52 stabilizes the roller tangent to its associated torio pitch circle.

Therefore. in order to tilt the rollers for initiating a speed ratio changing precession of the rollers. itis necessary to apply suicient tilting pressure to the roller control projections 62 to overcome the stabilizing effect of each roller driving-load reaction force against its nat abutment face 66.- Accordingly, the shifting force required to .be exl 8 erted against the control arm 86 for a speed ratio change bears a definite ratio to the magnitude of the driving-load, which ratio may be varied by suitably proportioning the width o! the stabilizing land or abutment face 88. With this construction, the operator can feel that the rate of speed change is proportional to the magnitude of the pressure applied to the control arm 80.

In Figure 5 the clearances between the support arm 50 or 52 and the walls of the slot 49 have been greatly exaggerated to help bring out the nature of the abutment faces 88. Figure 6 illustrates a roller journal member 48' which is a slight modification of the roller journal member 46 and similar parts have been indicated by slmilar but primed reference numerals. In Figure 6 the slot 49' is provided with an abutment face 66', the sides of which are abruptly cut back as indicated at 86' instead of being angularly relieved as in Figure 5. The roller stabilizing efl'ect of the roller driving load reaction between the roller support arms and their associated abutcarrier 44 and driven sleeve 46 are held stationary regardless of the speed of revolution of the main shaft I6 and input discs I6 and I6, i.,e., the transmission is in zero ratio. Control movement of the rollers towards greater angularity than shown will result in the driven member I 6 rotating in the same direction as the discs I6 and I6, whereas angulation in the other direction will result in the opposite rotation of the driven member 46. With the proportions shown, an overall ratio of 1:-1 is obtained with minimum radius contact on the middle disc 26 and maximum radius on the end discs I6 and I8 while a ratio of about l, in the opposite direction is f' afforded at the opposite extreme of the roller movement. Thus. by progressive movement oi' the control from one extreme to the other, the transmission goes from 1:1 progressively to zero ratio and therethrough into the opposite direction of rotation of the driven member. Attention is again directed to my prior Patent No. 2,079,683 for a more detailed description of this general operation whereby the transmission is sh'iftable from a drive in one direction through zero ratio to a drive in the reverse direction.

As described the facing toroidal surfaces preferably have a common pitch circle. However, in some prior art toroidal transmissions-such as disclosed in Patent No. 1,856,249 to F. A. Hayesthe pitch circles of the facing toroidal surfaces are displaced slightly relative to each other. The

amount of this displacement is small so that the expression common pitch circle in the appended claims is intended to be sufficiently broad to cover such slightly displaced pitch circles.`

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim' in the appended claims to cover all such mod# -iflcationa I claim as my invention;

1. In a variable speed transmission. a pair of discs having facing co-axial toric surfaces with a common toric pitch circle, a plurality of circumferentially spaced rollers disposed in driving engagement with the toric surfaces of said discs. means supporting each roller for speedratio-changing pivotal movement about individual axes tangent to said toric pitch circle, and control means operatively connected to said rollers and movable parallel to the axis of said toric surfaces for tilting each roller about individual axes passing through the points of contact of said rollers with said toric surfaces, said control means comprising a hub member and a rim member respectively disposed inwardly and outwardly of said rollers, and substantially radial arms extending between said rollers for interconnecting said rim and hub members.

2. In a transmission, a member, a roller disposed in driving contact with a surface of said member, a journal member for said roller, a support for said roller and journal member, and a pin carried by said support with its axis disposed at right angles to the axis of said journal member, said pin pivotally connecting said journal member to said support for speed-ratiochanging pivotal movement about the axis of said pin, the fit of said pin being sufficiently loose for tilting of said roller about an axis at right angles to the axis of said pin and roller journal member.

3. In a transmission, a member, a roller disposed in driving contact with a surface of said member, a journal member for said roller having a slot, a support for said roller extending within said slot, and a pin extending across said slot at right angles to the axis of said journal member and connecting said journal member to said support for pivotal movement about the axis of said pin, the t of said pin being suillciently loose for tilting said roller about an axis at right angles to the axes of said pin and journal member.

4. In a variable speed transmission, a pair of discs having facing co-axial toric surfaces,l a plurality of rollers disposed in driving engagement with the toric surfaces of said discs, a journal member for each roller, a support for each roller journal member, a pivot pin for each journal member, each of said pivot pins connecting its associated journal member with its support for speed-ratio-changing pivotal movement of its `roller about the axis of its associated pin the inherent lateral looseness of the t of each of said pivot pins permitting tilting of their associated rollers about individual axes through the points of contact of each roller with said toric surfaces, and means for effecting such -tilting of each said roller.

5. In a variable speed transmission, a pair of permitting tilting of their associated rollers about individual axes through the points of contact of each roller with said toric surfaces, and means for effecting such tilting of each said roller.

6. In combination, a pivotally mounted roller carrier member, a control member therefor, a unitary block, and a pin pivotally mounting said blockv on one of said members about an axis substantially parallel to the pivot axis of said roller carrier member, said block being engageable with a surface on the other of said members inclined to said axes.

'7. A push-pull connection between a first member mounted for pivotal movement and a second member movable along a linear path, said connection comprising a pair of parallel surfaces on one of said members and inclined both to the pivot axis of said pivotal movement and to said linear path, a block fitted to said surfaces. and a pin pivotally securing said block to the other of said members about an axis substantially parallel to said first mentioned pivot axis.

8. In a transmission, a member,I a roller -in driving engagement with a surface of said member, a vpivotally mounted journal member for said roller, and control means connected to said journal member for tilting said roller about an axis at right angles to the axis of said'journal member and its pivot axis. said connection including means restrained to pivotal movement about an axis parallelto the pivot axis of said journal member.

9. In a variable speed transmission, a pair of d iscs having facing co-axial toric surfaces, a plurality of rollers disposed in driving ,engage mentl with the toric surfaces of said discs, `a-jour nal member for each roller, means supporting each roller journal member for speed-ratiochanging pivotal movement across said toric 10. In a variable speed transmission', a pair of discs having facing co-axial toric surfaces with a common toric pitch circle, a plurality of circumferentially spaced rollers disposed between and in driving engagement with the toric surfaces of said discs, a journal member for each roller, means supporting each roller journal discs having facing co-axial toric surfaces with a common toric pitch circle, a plurality of circumferentially spaced rollers disposed in driving engagement with the toric surfaces of said discs. a journal member for each roller having a slot, a support for each roller comprising an arm extending within the slot of the associated roller faces formed on each f said roller journal members disposed' parallel to the associated roller axis of said journal member and inclined relative to the pivot axis of said journal member, a plurality of unitary members each fitted between a pair of said surfaces, a control'member movable parallel to the axis of said toric surfaces,

Al of the ilt of each of said pivot pins 1| and a plurality of pins, pivotally connecting said 11 unitary member to said control surfaces about individual axes parallel to the pivot axes of their v' associated journal members.

11. In a variable speed on comprising a pair of discs having facing co-axial' toric surfaces, a plurality of clrcumferentialiyT spaced rollers disposed in driving engagement with said surfaces, a journal member for each roller,

a pivot pin supporting each roller journal member for speed-ratio-changing pivotal movement of its roller across said toric surfaces about the axis of its associated pin, the fit of said pivot pins being sumcientiy loose for tilting of their associated roller Journal members about individu`al ares through the points of `contact of each roller with said toric surfaces, and control means having a pluralityof surfaces each respectively engageabie with a surface on one of said journal members for applying a roller tilting force thereto, at least one surface of each pair of said engageable surfaces being inclined to the pivot axis of` the associated journal 12. In a transmission, amember, a roller inv driving engagement with the surface of said member, means operable to tilt said roller for steering said roller across said surface. and roller supporting means comprising abutment faces urged together by the roller driving force reaction and arranged so that. upon roller tilt, u

said roller is urged back to its untilted position .with a force dependent on the magnitude of the toric surfaces andthe sides of'each associated arm and slot having clearance on both sides of saidzone.

16. In-a variable speed transmission comprising a pair of discs having facingcc-axial toric surfaces, a plurality of rollers disposed in driving engagement with the toric surfaces of said discs, a journal member for each roller, a support for each journal member arranged for speed-ratio-changing pivotal movement of each roller acrosssaid toric surfaces, and for tilting of each roller about individual axes passing through the points of contact of each roller with said toric surfaces, each said support and roller journal member having flat engaging faces subjected to the roller driving load reactions wheregy the driving load reaction exerted against said engaging faces tends to stabilize each said roller against said tilting movement with a force proportional to the magnitude of said driving load reaction.

17. In a variablev speed transmission compris- ;ing a pair of discs having facing co-axial toric surfaces with a common toric pitch circle, a plurality of circumferentiallyl spaced rollers disposed between and in driving engagement with the toric surfaces of said discs, a journal member for each roller having a slot, a support` for each roller comprising an arm extending within the slot of the associated roller journal member, a pivot pin for each roller disposed tangent to said toric pitch circle, each ofsaid pivot pins extending across the slot in its associated journal member and pivotally connecting its associated journal member and supporting arm, said arm and slot having an elongated'iiat contact zone subjected to the rollery driving force reactions, each of said elongated contact zones being disposed parallel to the tilt axes of its asso.-

' ciated roller and the sides of the associated arm of discs having facing co-axial toric surfacesga,

plurality of circumferentially spaced rollers disposed in driving engagement with Vsaid discs',

meanslsupporting each of said rollers for speedrati u ing pivotal movement vacross said toric aces and for -tilting movement about individ axes through the points of contact of each roller with vsaid toric surfaces, and means movable to effect said tilting movement. said roller supporting means comprising fiat abutment faces urged together by the rollerv driving force reaction and arranged so that upon transmission comprisu lng a pairl of discs having facing toric surfaces with a common toric pitch circle, a plurality of rollers disposed in driving engagement with the toric surfaces of said discs.' a journal member for each roller having a slot, a support for each roller comprising an arm extending within said slot. a pivot pin for each roller disposed tangent to said toric pitch `circle and pivotally connecting its associated journal member and supporting arm, said arm and slot having an elongated flat contact acne subjected to the roller driving ,force reactions, each of said elongated contact 4zones being [disposed parallel to a line through the points o'f contact of its associated roller with its of said second roller, and 'a unitary -control .frame engaging said-control means and movable to pivotthe rollers equally but in opposite direc'- tions. v

19. In a transmission, co-axial disc formed toroidally about a pair of pitch circles of given radius, two sets of pivots disposed at said radius. roller carriers mounted on said pivots, a 4control frame connected at greater and lesser radii with the carriers of respective sets, each connection including pivot means parallel to the associated mounting pivot, said control frame being movable to vpivot said roller carrier equally but in opposite, directions.

20; In a variable speed transmissionv comprising a pair of discs having facing toric surfaces, a plurality of circumferentially spaced rollers disposed between and in driving engagement with said discs, a set of roller support arms.

each of said arms respectively supporting one of said rollers for speed-ratio-changing pivotal movement across said toric surfaces and for tilting about an individual axis through its points of contact with said toric surfaces. a set of coners and being adapted to effect said roller tilting,

said sets of arms respectively extending in opposite directions from said rollers.

21. In a variable speed transmission, driving and driven means comprising two pairs of facing toric surfaces, said toric surfaces being co-axial and each pair having a common toric pitch circle, the end toric surfaces being formed on one of said means and the intermediate toric surfaces being formed on the other of said means, a set of rollers disposed between and in driving engagement with each pair of toric surfaces, a journal member for each roller, the journal members for. each set of rollers being mounted for pivotal movement about' individual axes tangent to their associated toric pitch circle and for tilting about individual axes through the points of contact of their associated rollers and the toric surfaces eng'aged thereby, and control vmeans operatively connected to said journal members for effecting said roller tilting, said control means being operatively connected adjacent the inner end of one set of journal members and being operatively connected adjacent the outer end of the other set of journal members.

22. In a variable speed transmission, an intermediate member having oppositely facing toric surfaces, a pair of end member co-axial with said intermediate member and disposed on opposite sides thereof, said end members each respectively having a toric surface facing one of the toric surfaces of said intermediate member, a set of circumferentially spaced rollers disposed in driving engagement with each facing pair of toric surfaces, the rollers of each set being supported for speed-ratio-changing pivotal movement across their engaged toric surfaces and for tilting about individual axes through their points rollers and having control arms operatively connected to each roller, said control arms extending outwardly from said hub portion to said one set 01' rollers and extending inwardly from said rim portion to said other set of rollers.

23. In a variable speed transmission, an intermediate member having oppositely facing toric surfaces, a pair of end members co-axial with said intermediate member and disposed on opposite sides thereof, saidv end membersl respectively having a toric surface facing one `of the toric surfaces of said intermediate member, a set of rollers disposed in driving engagement with each facing pair of toric surfaces, the rollers of each set being mounted for speed-ratiochanging pivotal movement across their engaged toric surfaces and for tilting about individual axes through their points of contact with their engaged toric surfaces, and means axially slid- 14 able through the hub of said intermediate member for effecting said roller tilting.

24. In a variable speed transmission, an intermediate member having oppositely facing toric surfaces, a pair of end members co-axial with said intermediate member and disposed on opposite sides thereof, said end members each respectively having a toric surface facing one of the toric surfaces of said intermediate member, a set of rollers disposed in driving engagement with each facing pair of toric surfaces, the rollers of each set being mounted for speed-ratiochanging pivotal movement across their engaged toric surfaces and for tilting about individual axes through their points of contact with their engaged toric surfaces, anda unitary control frame operatively connected to respective sets of rollers adjacent opposite sides thereof and being axially slidable to tilt said rollers and efy fect equal but opposite speed-ratio-changing pivotal movement of said sets of rollers.

25. In a variable speed transmission, a pair of discs having facing co-axial toric surfaces with a common toric pitch circle, a plurality of circumferentially spaced rollers disposed between'and in driving engagement with said surfaces, a supporting structure for said rollers, a plurality of pins each carried by said supporting structure tangent to said toric pitch circle for respectively supporting one of said rollers for speed-ratio-changing pivotal movement about the axis of its associated pin, the t of said pins being sufficiently loose for tilting of their respective rollers about individual axes through the points of contact of each roller with said toric surfaces, and control means operable to effect such tilting of said rollers.

26. In a variable speed transmission, co-axial discs forming two pairs of facing toric surfaces, two sets of circumferentially spaced rollers, the rollers of each set being disposed in driving engagement between the toric surfaces of a pair of said discs. means for supporting each roller for speed-ratio-changing pivotal movement relative to said toric surfaces, and a control frame adapted to tilt said rollers about individual axes through the points of contact of said rollers with their toric surfaces', said frame being operatively connected to respective sets of rollers adjacent opposite sides thereof such that movement of said control frame effects pivotal movement of the rollers of one set in one direction and equal but opposite pivotal movement of the rollers of the other set.

ROLAND CHILTON.

REFERENCES CITED The following references are of record in the flle of this patent:

`UNlI'I'ED STATES- PATENTS Number Name Date 1,774,175 Erban Aug. 26, 1930 1,903,228 Thomson Mar. 28, 1933 1,947,044' Gove Feb. 15, 1934 2,108,082 Sharpe Feb. 15, 1938 2,113,638 Almen Apr. 12, 1938 FOREIGN PATENTS Number Country Date 415,922 Great Britain Sept. 6, 1934 

